Cataract surgery + toric implant 2 eyes

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Requested procedure: Cataract surgery + toric implant 2 eyes

All you need to know about cataract surgery

WHAT IS A CATARACT ?

A cataract is a clouding of the eye’s lens which leads to gradual sight loss. Most of the time it is caused by ageing, but very occasionally it can occur in younger people. This is a degenerative condition in the same way that arthritis is. It is not usually a serious risk to health, but it can become extremely annoying, even incapacitating. However, cataracts rarely require urgent treatment. Cataracts are still the number one cause of blindness in the world, affecting almost 20% of over 65s, more than 35% of those over 75 and 60% of those aged over 85.

WHO IS TYPICALLY AFFECTED BY CATARACTS ?

In the vast majority of cases, cataracts result from old age. By the age of 65 and over, people are much more likely to be affected by cataracts. However, cataracts may be caused by other factors: metabolic (diabetes, calcium metabolism disorders), poisoning (too-high levels of copper and iron), certain medications (mostly cortisone-linked) and trauma. Intraocular surgical procedures may also cause cataracts, as may inflammatory diseases. People who are already affected by certain eyesight issues such as severe short-sightedness are more likely to be at risk from this condition. To sum up, cataracts are caused by the ageing of the eye’s lens.

WHEN IS THE RIGHT TIME TO GET IT CHECKED OUT?

The first signs of a cataract are a reduction in visual acuity (clarity of vision), especially at long-distance. Near vision is not usually affected to begin with. The eye finds it harder and harder to bear bright lights, which is why people affected in this way will sometimes close their curtains even in the middle of the day. As the condition worsens, the victim feels cut off from their immediate environment and may experience failure to thrive syndrome. It’s not unusual for hearing loss to occur at the same time. Under these circumstances, it is essential to consult an eye doctor who will sometimes recommend a more thorough assessment be carried out.

WHAT ARE THE BENEFITS OF TREATMENT?

People often decide to seek treatment once the cataract or cataracts have started to have a major negative impact upon their everyday life. It’s therefore usually the patient who will decide to have the cataract treated. In specific cases, the eye doctor will expedite the decision to treat the cataract: – If a cataract is causing or exacerbating glaucoma – If the cataract makes it harder to perform a dilated fundus examination (particularly relevant in monitoring for diabetic eye disease). – Objective testing reveals advanced stage cataracts and poor visual acuity which could pose a risk to the patient or to others, even if the patient is not complaining of discomfort. It’s worthwhile remembering that old age is no barrier to treatment.

WHAT TREATMENTS OR PROCEDURES ARE USED TO TREAT CATARACTS?

At the present time, the only effective way of treating a cataract is via surgery. There is currently no preventive treatment for cataracts. The most common approach used is phaco-emulsification (using an ultrasonic probe) and the insertion of a foldable lens. Laser treatment remains a little-known option which is expensive and no better than the ultrasonic approach. It cannot be used to treat all types of cataract and it is above all of interest as an avenue of research. This explains why its use is not widespread. New surgical techniques make it possible to perform very small incisions (2 to 3 mm) which are far less likely to require stitches than was the case before. Once the cataract has been emulsified by ultrasound waves and sucked away, a completely clear implant is inserted in its place. This implant is usually flexible, it can be inserted through the small incision made in the cornea and folds out inside the eye. This lens is made from acrylic glass or silicone. The anaesthesia administered may range from general anaesthetic (rare, but recommended in certain cases), to peribulbar anaesthesia which consists of the injection of anaesthetic into the orbit of the eye, where it can work on the eyeball. This is still a very common technique, but it is rapidly being dropped in favour of the topical anaesthesia approach. This involves the instillation of anaesthetic in the shape of eye drops, with no injection needed. Pain or discomfort is generally restricted to the surface of the eye during the operation, and these drops are usually enough to resolve this. The standard duration of this procedure is between 10 and 20 minutes, but it may be longer if the surgeon decides it is necessary to proceed more slowly, if the patient is not easy to work with or if complications (even minor ones) occur.

AFTER CATARACT SURGERY

Various kinds of dressing may be applied to the eye, ranging from a dressing, application of ointment and keeping the eye completely closed to applying eye drops a couple of hours after the operation. The patient can return home on the same day as the operation. It is recommended to rest for a while. They must keep their eyeshield on and follow their eye doctor’s instructions. If the patient is experiencing increasingly severe pain which is not remedied by taking medicine (e.g. paracetamol), they must contact the clinic or surgeon that carried out the procedure or else get in touch with a centre offering emergency eye treatment. The patient will usually see the eye doctor the day after the operation for their post-operative check-up. This check-up may be postponed by a day or two, as long as the patient has been fully briefed on all the steps that they must take as part of the post-operative care of the eye. In this case, the patient should also be able to contact their eye doctor by telephone if necessary.

THE EFFECTIVENESS OF CATARACT SURGERY

Cataract surgery is generally very effective as long as the procedure has been correctly indicated and the operation was conducted without complications (which is increasingly the case). The length of time it takes for the impact on your eyesight to become apparent may vary: it may already be far superior by the next day, get better gradually or you may only notice a slight improvement if the other components of the eye are not in good enough condition (macula, optic nerve). The improvement in vision and the impact this has on everyday life is especially marked in the case of driving a vehicle. Some studies have estimated that the likelihood of you having an accident on the road is cut by 50% after this operation.

DIFFERENT IMPLANTS FOR CATARACT SURGERY

The oldest material used is acrylic glass, which is rigid and related to Perspex. This material consistently gives excellent results as far as vision is concerned. The major disadvantage of this approach is that it requires a larger incision to be made, which is not without its problems. These implants are used less and less frequently. Related materials are hydrophilic and hydrophobic acrylic, which are foldable. Silicone implants are also available. These are foldable too.

During cataract surgery, the eye’s natural crystalline lens is removed from the capsular bag. To correct this absence of lens (aphacia), the lens is replaced by an artificial intra-ocular lens. This is made out of an inert (non-reactive) acrylic which is not subject to deterioration. Acrylic is a flexible member of the Perspex family. Its use in intra-ocular lenses was first suggested at the end of World War II by Sir Harold Ridley, who noticed that Spitfire pilots who sustained eye injuries from the shattering of their Perspex windshields did not present any of the usual signs that a foreign body in the eye would normally cause…

These implants, like traditional contact or spectacle lenses, serve to rectify the eye’s optical shortcomings. There are many kinds of implants, here is a list of their key characteristics:

MONOFOCAL LENSES:

This implant aims to rectify simple conditions like short- or long-sightedness. These lenses are usually designed to filter out harmful UV-A and blue light at certain wavelengths which can damage the retina. We use aspheric or ‘aberration-free’ lenses, which are less prone to decentration and deliver better quality of vision, including during the night, when the pupils will naturally dilate.

Advantages:

Quality of vision is often excellent and the transition to the new lenses is fast and easy;

These lenses can be used to correct extreme cases of ametropia (severe short- or long-sightedness)

Any remaining shortcomings can be corrected by wearing ordinary spectacles.

It is necessary to choose which kind of vision you are aiming to prioritize before the operation, i.e. either distance vision, in which case you aim to achieve emmetropia or else close vision, when you aim to reach a standard of residual short-sightedness (the two goals can be combined, with one eye for distance vision and one for close vision, although this results in some loss of binocular vision).

TORIC LENSES:

This is a development of the monofocal lens, the lens being capable of correcting astigmatism, as well as containing a sphere component (correction of short- or long-sightedness).

This kind of implant requires a pre-operative assessment including an accurate corneal topography to assess corneal astigmatism. This means the iimplant is tailored to your eye.

The axial positioning of the implant must be as close as possible to that decided on at the pre-operative stage. If the implant‘s positioning is out by just a few degrees it may result in the astigmatism being only partially corrected, or not corrected at all.

If this happens, another operation may be undertaken to correct the positioning. The patient may also end up needing to wear spectacles.

MULTIFOCAL LENSES:

Optically-speaking, these implants work by distributing light via diffractive optics, focusing 2 images (bifocal) or 3 images (trifocal) onto the retina at the same time.

Advantages:

Patients can see objects at a distance, in the middle-distance and close-up without spectacles, using bifocal lenses or trifocal lenses.

These implants enable patients to do away entirely with spectacles.

They have been in use for many years and deliver very good quality of vision.

Disadvantages:

They require extremely precise placement in order to avoid the risk of astigmatism, as well as the accurate calculation of the required lens power at the pre-operative stage.

The diffractive optics can create optical aberrations such as halos around light sources and greater sensitivity to glare, especially in the first few weeks after the operation and at night-time.

These effects may become less apparent over time, but they may also linger and can make night-driving more difficult. As a result, these implants are not recommended for those who drive a vehicle for a living (taxi drivers, ambulance drivers, HGV drivers…)

These implants need well-lit conditions to deliver optimal quality of vision. Sometimes it may be difficult to read in poor light conditions and reading glasses may be necessary.

EDOF/ERV LENSES:

Extended Depth Of Focus/Extended Range of Vision lenses are multifocal lenses with a slightly different approach which involves the correction of longitudinal chromatic aberrations and a diffractive echelette design to correct both distance and close vision issues.

Advantages:

These lenses help correct difficulties with a person’s vision by reducing the impact of optical aberrations (especially halos)

Disadvantages:

The first generation of EDOF/ERV lenses are a little less effective when it comes to close vision, meaning that they need to be combined with spectacles for close work on a more frequent basis

MULTIFOCAL TORIC LENSES:

These implants can correct all eyesight issues, including astigmatism. They require absolutely accurate pre-operative measurements and lens power calculations; the lens must be implanted and centred with pinpoint precision and the patient’s brain must be able to adapt to the new lens. As a result, these lenses are much more prone to requiring tweaks, repositioning or replacement than other types of lens.

The Interophta cataract surgery pre-operative procedure

1/ Medical case history

2/ Testing visual acuity (clarity of vision)

3/ Testing intraocular pressure

4/ Clinical examination using a biomicroscope (slit lamp) to look at the back of the eye and the peripheral retina with a contact lens (single-use)

7/ Corneal topography performed by Scheimpflung camera (Pentacam) with crystalline lens density analysis. Specialist software in cataract pre-operative mode, enabling a number of elements relating to the cornea to be analyzed, the depth of the anterior chamber of the eyeball, along with the biometry enabling a more accurate calculation of the power of the intra-ocular lens implant to be carried out. Toric lens implants make it possible to measure anterior corneal astigmatism separately from posterior corneal astigmatism and allow for a more accurate measurement of the axis and cylinder power.

8/ Optical coherence tomography angiography without the use of dye injections (Optovue), enabling an accurate analysis of the retina and macular region, especially in relation to blood flow. This examination also looks at the optic nerve head and the ganglion cell complex.

9/ In the event of a white cataract or difficulties obtaining axial length measurements, a B-scan ultrasound (10 MHz) will be used to examine the deeper parts of the anterior chamber. If needed, a high-frequency (50 MHz) ultrasound biomicroscopy (UBM) will also be carried out.

10/ An A-scan ultrasound, which requires contact with the cornea, can be used to obtain axial length measurements.